-
Notifications
You must be signed in to change notification settings - Fork 2.8k
/
ListenDataSnippets.java
215 lines (190 loc) · 6.74 KB
/
ListenDataSnippets.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/*
* Copyright 2018 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.firestore.snippets;
import com.google.api.core.SettableApiFuture;
import com.google.cloud.firestore.DocumentChange;
import com.google.cloud.firestore.DocumentChange.Type;
import com.google.cloud.firestore.DocumentReference;
import com.google.cloud.firestore.DocumentSnapshot;
import com.google.cloud.firestore.EventListener;
import com.google.cloud.firestore.Firestore;
import com.google.cloud.firestore.FirestoreException;
import com.google.cloud.firestore.ListenerRegistration;
import com.google.cloud.firestore.Query;
import com.google.cloud.firestore.QuerySnapshot;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import javax.annotation.Nullable;
/**
* Snippets to demonstrate Firestore 'listen' operations.
*/
@SuppressWarnings("Convert2Lambda")
public class ListenDataSnippets {
private static final long TIMEOUT_SECONDS = 5;
private final Firestore db;
ListenDataSnippets(Firestore db) {
this.db = db;
}
/**
* Listen to a single document, returning data after the first snapshot.
*/
Map<String, Object> listenToDocument() throws Exception {
final SettableApiFuture<Map<String, Object>> future = SettableApiFuture.create();
// [START listen_to_document]
DocumentReference docRef = db.collection("cities").document("SF");
docRef.addSnapshotListener(new EventListener<DocumentSnapshot>() {
@Override
public void onEvent(@Nullable DocumentSnapshot snapshot,
@Nullable FirestoreException e) {
if (e != null) {
System.err.println("Listen failed: " + e);
return;
}
if (snapshot != null && snapshot.exists()) {
System.out.println("Current data: " + snapshot.getData());
} else {
System.out.print("Current data: null");
}
// [START_EXCLUDE silent]
if (!future.isDone()) {
future.set(snapshot.getData());
}
// [END_EXCLUDE]
}
});
// [END listen_to_document]
return future.get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
}
/**
* Listen to a query, returning the names of all cities in the first snapshot.
*/
List<String> listenForMultiple() throws Exception {
final SettableApiFuture<List<String>> future = SettableApiFuture.create();
// [START listen_to_multiple]
db.collection("cities")
.whereEqualTo("state", "CA")
.addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@Nullable QuerySnapshot snapshots,
@Nullable FirestoreException e) {
if (e != null) {
System.err.println("Listen failed:" + e);
return;
}
List<String> cities = new ArrayList<>();
for (DocumentSnapshot doc : snapshots) {
if (doc.get("name") != null) {
cities.add(doc.getString("name"));
}
}
System.out.println("Current cites in CA: " + cities);
// [START_EXCLUDE silent]
if (!future.isDone()) {
future.set(cities);
}
// [END_EXCLUDE]
}
});
// [END listen_to_multiple]
return future.get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
}
/**
* Listen to a query, returning the list of DocumentChange events in the first snapshot.
*/
List<DocumentChange> listenForChanges() throws Exception {
SettableApiFuture<List<DocumentChange>> future = SettableApiFuture.create();
// [START listen_for_changes]
db.collection("cities")
.whereEqualTo("state", "CA")
.addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@Nullable QuerySnapshot snapshots,
@Nullable FirestoreException e) {
if (e != null) {
System.err.println("Listen failed: " + e);
return;
}
for (DocumentChange dc : snapshots.getDocumentChanges()) {
switch (dc.getType()) {
case ADDED:
System.out.println("New city: " + dc.getDocument().getData());
break;
case MODIFIED:
System.out.println("Modified city: " + dc.getDocument().getData());
break;
case REMOVED:
System.out.println("Removed city: " + dc.getDocument().getData());
break;
default:
break;
}
}
// [START_EXCLUDE silent]
if (!future.isDone()) {
future.set(snapshots.getDocumentChanges());
}
// [END_EXCLUDE]
}
});
// [END listen_for_changes]
return future.get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
}
/**
* Demonstrate how to detach an event listener.
*/
void detachListener() {
// [START detach_errors]
Query query = db.collection("cities");
ListenerRegistration registration = query.addSnapshotListener(
new EventListener<QuerySnapshot>() {
// [START_EXCLUDE]
@Override
public void onEvent(@Nullable QuerySnapshot snapshots,
@Nullable FirestoreException e) {
}
// [END_EXCLUDE]
});
// ...
// Stop listening to changes
registration.remove();
// [END detach_errors]
}
/**
* Demonstrate how to handle listening errors.
*/
void listenErrors() {
// [START listen_errors]
db.collection("cities")
.addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@Nullable QuerySnapshot snapshots,
@Nullable FirestoreException e) {
if (e != null) {
System.err.println("Listen failed: " + e);
return;
}
for (DocumentChange dc : snapshots.getDocumentChanges()) {
if (dc.getType() == Type.ADDED) {
System.out.println("New city: " + dc.getDocument().getData());
}
}
}
});
// [END listen_errors]
}
}